Lateral electronic transport in short-period InAs/GaAs superlattices at the threshold of quantum dot formation

Abstract

Temperature dependences of resistance at 0.7 K<T<300 K, the Hall and Shubnikov-de Haas effects in magnetic fields of up to 40 T, photoluminescence (PL), and morphology of a heterointerface (using an atomicforce microscope) of short-period InAs/GaAs superlattices were investigated. The investigations were carried out for a region of subcritical and critical thickness Q=2.7 monolayers (ML) of InAs. Upon exceeding the critical thickness, the self-organized growth of InAs quantum dots (QDs) set in. The formation of QD layers upon exceeding the critical thickness of InAs Q=2.7 ML is accompanied by a transition of conductivity from metallic to hopping. It is found that at InAs layer thicknesses of Q=0.33 ML and Q=2.0 ML, the PL intensities and electron mobilities in the structures have clearly pronounced maxima. Anisotropy of conductivity, which depends on the thickness of the deposited InAs layers, was observed.